im after a way to build myself a tail pipe like the ones you use on the larger turbines on a lambert kolibri the priobelm i have is where is comes out the plane its close to composite and i thought if the tailpipe was like the self cooling ones that they use that might help to cool it down does anyone have a sugestion on how to build one and obveiously it would have to be reasonably light the one that lambert selld is a basic round tailpipe no cooling

A twin walled pipe is what you would need to make, the trust tube sits inside a slightly larger pipe which at the turbine end has a bellmouth fitted so that cool air entering the fuselage is directed through this secondary pipe as well as through the turbine, keeps the temps down but adds weight naturally...... The other option is to add some heat shield material like BVM's ceramic heat shield blanket or the BVM ceramic heat shield paint (at least 3 layers).

marcs

The Wren pipes are single wall but they give details on making the outer pipe from litho plate (thin aluminium).
This is what I did for a pipe for my Super Sport. - John.